Thoughts on Using Helicoil (in this case for Transmission Pan Bolt)

aa040371 said:

During a DIY transmission fluid service (not the actual discussion topic, please!) one of the ~20 pan bolts broke off while removing the pan, leaving a chunk in the bolt hole. Tried a left-hand drill bit and and Easy-out extractor, but to no avail, although there is now a path/hole through the hole, it just still has some of the old bolt still in the hole that won't dislodge for some reason.

I replaced pan and re-filled fluid and watched carefully over time/driving to see if any fluid was leaking...so far so good, but it's only been a day. I've no intention of leaving it this way, but would appreciate some advice or thoughts on best path forward.

My best efforts at investigation seem to point me toward Helicoil solution. Also, is this something a numb-nutted numb-nut such as myself should attempt, or best left to a mechanic?

Thoughts?

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Metal Head said:

If it's not leaking leave it alone. Like you said 19 other bolts holding that pan on and it's not under any pressure.

I've run a machine shop for 20 years. I've seen customers do way more damage than good trying to get bolts out. You'd still have to get the bolt out to put a helicoil in. Chances are doing it by hand under the truck you'll end up drilling the hole off center and/or snapping off a drill or tap inside.

If it weeps you'd be better off pulling the pan again and using some RTV along with the gasket to get it to seal off rather than messing with the bolt.

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aa040371 said:

Yep...agree. It's a little strange to me that I heard several times, from different avenues/sources/persons, "Helicoil, Helicoil, Helicoil!" I suspect not one of them had ever actually had to remove, re-tap, and insert a Helicoil, but probably just wanted project "knowledge"!

Happily, I found out I have in my network a former Army mechanic that worked on vehicles large and small, including Apaches and Black Hawks, as well as being a professional BMW/German car mechanic for years while living in Germany. He took care of the issue, without needing a Helicoil, in about 15 minutes such that a new transmission pan bolt I had just picked up from Toyota stealership went right in as usual/normal, so...hooray.

And he's the guy that also recommended (well...ordered, really) me to use Liqui-Moly products, which is pretty much all I use in my vehicle now when it comes to lubrication or additives.

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AuSeeker said:

Do you know how he was able to remove the broken bolt so quickly?

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